Startup of An Anaerobic Hybrid Reactor Treating Petrochemical Wastewater

Wastewater is the main point-source pollutant on a global scale. Between 90 and 95% of the sewage produced in the world is released into the environment without any treatment. ِDevelopment of petrochemical industry in IRAN, construction of new plants and up gradation of existing units, has lead to generate more wastewater of higher strength. Some kinds of aerobic and anaerobic processes are applied for treatment of this type of wastewater. Performances during startup of a anaerobic hybrid reactor (UASB/Filter) treating petrochemical wastewater at mesophilic condition were investigated. The reactor was seeded with flocculent sludge from a UASB plant treating dairy wastewater. The reactor was run for 5 months without adaptation but it was unsuccessful. Hence the adaptation of sludge considered in 2 stage operation. At the first stage, the synthetic wastewater made from dry milk was fed to the reactor. After 65 days, the performance of reactor was 77. 8 percent at OLR=2. 0 kg/m3. day and HRT=18 hrs. Then in stage 2, The COD part of feed related to petrochemical wastewater increased step by step at 10 percent increments (increased COD mass of petrochemical wastewater by 10% per cycle) and injected to reactor completely from petrochemical wastewater. After 30 weeks, a COD removal of 70. 3% was obtained at OLR=2. 0 kg/m3. day and HRT=18 hrs.